In the 571-page book, “The Black Banners: The Inside Story of 9/11 and the War Against Al Qaeda,” Mr. Soufan accuses C.I.A. officials of deliberately withholding crucial documents and photographs of Qaeda operatives from the F.B.I. before Sept. 11, 2001, despite three written requests, and then later lying about it to the 9/11 Commission.

He recounts a scene at the American Embassy in Yemen, where, a few hours after the attacks on New York and Washington, a C.I.A. official finally turned over the material the bureau requested months earlier, including photographs of two of the hijackers…

Mr. Soufan recounts how he began a promising interrogation of a knowledgeable Qaeda member, Abdullah Tabarak, at Guantánamo Bay, Cuba, only to be told by the military authorities that he could no longer speak to the prisoner. He later learned the prisoner was sent to Morocco and subsequently released.

“There are some politicians and bureaucrats who live in an alternate universe, who are invested in that small part of the program and defend it regardless of facts,” he said